With government and defense applications seemingly never having enough radio communications bandwidth, radio supplier FreeWave Technologies has added several 2.4-GHz board-level radios to its Spartan Series of products. The latest Spartan radio is well suited for command-and-control (C2) links in unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) where minimizing size, weight, and power are chief concerns. The unit includes Federal-Information-Processing-Standard (FIPS) 140-2 Level-2 encryption, along with 32-b cyclic-redundancy-check (CRC) error detection with automatic retransmission [enabling reliable data communications at line-of-sight (LOS) distances to 60 miles].

The new user-programmable Spartan radio card (see figure) is available with a serial interface; it operates with output-power levels of 20 to 500 mW by means of seven user-selectable frequency-hopping bands working across a total bandwidth of 2.400 to 2.843 GHz. The occupied bandwidth is only 230 kHz. The radios feature two-level Gaussian-frequency-shift-keying (GFSK) modulation. The selectivity is typically 20 dB within 230 kHz of the operating center frequency. The radios offer user-selectable data rates of 115 or 153 kb/s with nominal sensitivity of -103 dBm at a data rate of 153 kb/s and 1 x 10-6 bit-error rate (BER) and -106 dBm at a data rate of 115 kb/s and 1 x 10-6 BER.

The different models are the M24-NCF radio with serial interface, measuring 106.7 x 50.8 x 14.1 mm, and the M24-NCF-CC, which is a conformal-coated version of the M24-NCF. The radios—which are supplied with MMCX connectors, and weigh 66.9 g or less—are available with RS-232 protocols, supporting data interfaces operating at rates of 1.2 to 115.2 kb/s. They work on supply voltages from +4.75 to +5.25 VDC and typically draw 1200 mA current at +5 VDC in transmit mode, 240 mA at +5 VDC in receive mode, and 135 mA at +5 VDC in idle mode.

The firm claims more than 75,000 radios in the field for government and defense data-transmission applications. With their FIPS 140-2 Level 2 crypto algorithm, these radios support counter mode, which uses a sequence of blocks to encrypt data that is never repeated. This makes critical data more secure than data sent using the standard authenticated encryption scheme (AES) codebook, where a given block of data will always return the same encrypted block of data.